1. Field of the Invention
The present invention relates to a projection apparatus, a projection method, and a program which are suitable for a projector apparatus or the like.
2. Description of the Related Art
Various projector apparatuses have been commercially available which use a scheme called a field sequential scheme to enable color images in a plurality of colors to be visually perceived by switching the images at a high speed to consecutively project the images.
In particular, for projector apparatuses of this kind which use LEDs as a light source, a technique can be used which simultaneously lights LEDs in a plurality of colors, R (red), G (green), and B (blue), which serve as a light source, in order to ensure a sufficient quantity of light.
FIG. 5 illustrates the emission luminance of each of the color LEDs obtained when one image frame is divided into three fields to project the respective RGB color images. FIG. 5(A) shows timings (fields) when for example, an LCD panel or a micromirror element forming optical images forms color images.
For example, in the R field, a red LED-R shown in FIG. 5(B) can emit light at a high current value. At the same time, a green LED-G shown in FIG. 5(C) and a blue LED-B shown in FIG. 5(D) can emit light at a preset low current value. The resulting mixed light forms a red optical image.
FIG. 6 is a CIExy chromaticity diagram illustrating a comparison of a chromaticity set when such multicolor LEDs as described above are simultaneously driven to emit light, with a chromaticity set when a single-color LED is lit. In FIG. 6, a horseshoe shape indicates a human visible region V. Furthermore, dashed lines and circles at vertex positions show the range of the chromaticity set by the single-color LED. On the other hand, solid lines and triangles at vertex positions show the range of the chromaticity set by the multicolor LEDs.
LEDs have a property wherein not only luminance but also chromaticity varies with the value of a supplied current. Thus, when the apparatus actually operates, if LEDs in three colors are made to emit light, for example, in an R field of one frame, the resulting mixed light has an unexpected chromaticity owing to the above-described property.
If the chromaticity of the light source varies in at least one of the R, G, and B fields, the chromaticity in one frame as a whole may also vary. This prevents projection from being achieved at the correct chromaticity.
As described above, an object of the present invention is to provide a projection apparatus, a projection method, and a program which enable the chromaticity of light source light according to the field sequential scheme to be accurately maintained at a set content.